We aim to review the effects of chemotherapy on skeletal muscle mass and cardio-respiratory performance in patients with oesophageal adenocarcinoma. All patients will be assessed by a Consultant Anaesthetist and a medical member of the Research team before commencing chemotherapy and after finishing their course. These assessments include a nutritional assessment, performance status assessments, blood assays, dual energy X-ray absorptiometry (DEXA) scans, cardio-pulmonary exercise (CPEX) testing and a muscle biopsy.